The present invention relates to digital cameras and more particularly to a device for recording/reproducing a still picture suitable for image inputting means for a computer, etc.
Since, in video cameras, various functions have been developed as the signal processing is performed in a digital manner and digital video signals are easily output, the cameras have been marked as video inputting means for computers. Though, a lower price image inputting means can be provided by utilizing parts of commercial based single-unit video camera-recorder as much as possible into a digital camera used as image inputting means, only special inputting means such as a line scanner has been provided at present.
In order to provide the low price video putting means, the following important problems must be solved:
1) The automatic control system should be applicable to a still picture--In a general video camera, exposure control and white balancing control are provided using a video signal. No sensors for illuminance and color temperature are provided as separate means. The illuminance and color temperature are sensed from the video signal and fed back to the controller. However, those data cannot be fed back to the still picture; PA1 2) A still picture of the frame should be produced using a general image pickup unit--A general image pickup unit is of a destructive read type in which a pixel signal can be read only once and also of a pixel mixing type in which two pixels adjoining in the vertical direction are mixed and read out. Signal processing in this reading system produces no still picture having a resolution corresponding to the number of pixels; PA1 3) A general-purpose image pickup unit should be applicable--After the video signal is input to a computer, an operation such as rotation can be performed on an image in graphics. In this case, no distortions should be invited in the image. To this end, a subject is required to be subjected to opto-electric conversion at spatial sampling pitches equal in the horizontal and vertical directions. To this end, an image pickup unit in which pixels are disposed in a same distance in the horizontal and vertical directions is required to be used. However, in an image pickup unit used generally in a camera integral with a domestic VTR, the pixels are disposed at different intervals in the horizontal and vertical directions; and PA1 4) The capacity of recording means which records a still picture should be minimized--In order to record a still picture with RGB signals which are a general video signal taken into a computer, addresses are required for the respective R, G and B signals to thereby increase the recording capacity.